This invention relates to a manipulator arm such as are in common use today with robot like equipment, and in particular to a new and improved apparatus for changing of tools and the like which are carried by manipulator arms.
In a conventional configuration, an arm is remotely controlled, often automatically by a predetermined program, for moving a tool or the like along various paths to accomplish various desired aims. The tool or other item carried by a manipulator arm is often referred to as an end effector, and that nomenclature will be used herein. During the use of the manipulator arm, it is often desired to utilize more than one end effector in an operating sequence and therefore it is necessary to change end effectors between steps of the sequence.
Various arrangements are utilized for changing end effectors with manipulator arms, including various arrangements for manually connecting and disconnecting the end effector.
Automatic machine tools which perform a variety of metal working operations in sequence have been developed and automatic changing of tools is a feature in many of these machines. Two such devices are shown in U.S. Pat. Nos. 4,204,303 and 4,216,572. In these devices, a plurality of tools is positioned in a frame located between a drive source and the work piece. In operation, the frame is rotated to place the desired tool in line between the drive source and the work piece, and then the drive source is actuated to engage the tool and perform the desired operation. The type of work which can be performed by this type of equipment is severely limited, in contrast to the work which can be performed by the robot type manipulator arm having many degrees of freedom in the motions available.
Another type of end effector or tool changer is shown in U.S. Pat. No. 4,145,802. In this device, a plurality of tool carriers is mounted in a rack, and a power source is movable to be selectively positioned at each of the end effectors. The power source is engaged with the selected end effector by energizing an electromagnet which holds the end effector to the power source and engages the tool drive mechanism. This type of device suffers from the disadvantage of requiring a separate control function, namely energizing and deenergizing of an electromagnet, in order to effect the engagement of the power source with the end effector.
Accordingly, it is an object of the present invention to provide a manipulator system tool changer for using more than one end effector in the performance of one or more operations without need for manual attachment or detachment or for the use of any other powered or mechanical means or transmission of signals for the attachment or detachment of different end effectors. A further object is to provide for automatic changing of the end effector by means of a linear motion of the attachment point of the manipulator arm.
The tool changer system of the invention permits the use of multiple end effectors in circumstances in which manual or separately powered or signaled detachment and attachment means would not be practical or would increase work cycle time. The manipulator arm may be under direct manual control, remote manual control, manual control through a processing system, and automated control, as in manipulator arms which constitute or are elements of cam-operated machines, material handling and transfer devices, and robots. While tools are usually referred to herein as being carried by the end effector, the invention is not limited to a conventional cutting tool or wrench or the like, and the word "tool" is used broadly to include all types of devices used by robot type equipment, including sensors, transducers, hands, scoops, etc.
It is an additional object of the invention to provide a tool changer suitable for remote control operation of a manipulator arm which might be stationary or vehicular-mounted to increase the nature of tasks which may be accomplished, and to remove and to replace worn or broken end effectors. Holders with alternative end effectors can be mounted on the carriage of mobile manipulators, with manipulator action necessary to accomplish the detachment and attachment of different end effectors performed by remote control, or by pre-programmed automatic triggered manual control, sensor signal, accumulated time or work cycle.
A further object of the invention is to provide an automatic tool change system suitable for use on a flexible machine assembly station in manufacturing to permit a single manipulator to accomplish a wide range of actions such as: workpiece pick and place; sensor manipulation for code reading; camera manipulation for remote viewing, image recording, and workpiece orientation determination; pick and place of a variety of shapes requiring different end effectors to allow manipulation of the workpiece, gauges, packing materials, and replacements of worn cutting heads; performing cutting, grinding, burnishing, polishing, drilling, and other operations upon the workpiece by the manipulation of powered equipment or through the action of the manipulator in its movement of the end effector; cleaning, coating, abrading, and heating operations using gas or liquid flow through the system through a nozzle involving one or more gases and/or fluids and with the capability to incorporate reservoirs for fluid, dust and gas; performing flame treatment operations as by the manipulation of a torch nozzle and ignitor, and incorporating the operating signal, igniting energy, and gas and fluid flow through the system or by incorporation of appropriate reservoirs.
It is an additional object of the invention to provide a tool changer with which energy may be transmitted from the manipulator arm to the end effector. Such an energy transmitting manipulator end effector system allows industrial robots to service one or more machine tools or other processing equipment with capability to handle, perform sensory operations upon, and perform processing work efforts upon, a wide variety of workpieces, gauges, and tools in support of flexible machining processes. Use of robots in flexible assembly operations and the automation of assembly involving a variety of shapes, sizes, and operations to be performed has been restricted by the limited capacity of even multi-functional end effectors. The system of the present invention allows the robotic manipulator to be programmed to automatically change end effectors which permits the manipulation of a wide variety of objects, and the performance of tasks necessary in the course of assembly such as placing and fastening by rivet or bolt, forming quality control checks during assembly operations, and operating with grippers requiring controlled but wide range of gripping force to handle objects of different size, weight, and sensitivity to force.
It is an object of the invention to provide a system which allows manipulators to detach and attach different end effectors through a simple one-motion operation without need for additional power or signals to accomplish the attachment and detachment. Such a system greatly increases the flexibility of use of manipulators and provides for the transmission of energy and communication through secure, safe, and non-leaking connections made between components of the system.
It is a particular object of the invention to provide such a tool changer incorporating a two member coupling, with one member carried by a manipulator arm and the other member carried by an end effector, with the coupling member being engaged by a compression force and disengaged by a tension force, i.e., operated by a simple push and pull motion without requiring additional motions or control functions. The coupling member may be constructed integral with the manipulator arm and/or end effector or tool, or may be separately constructed and attached by conventional means.
Other objects, advantages, features and results will more fully appear in the course of the following description. Preferred embodiments of the present invention are given by way of illustration or example in the drawings and description.